The transfer and distribution of goods is expensive in both time and manpower, and contribute to the cost of goods. Pallets used in combination with the forklift have produced substantial economies in the movement of goods by providing many different goods with a similar interface, allowing mechanization and unitization of goods. Nevertheless, the pressure to reduce the cost of supplying goods continues to drive a search for improvements in distribution.
Industrial article handling systems are well known for stacking layers of articles on a pallet. The articles may be cans, containers, bottles, cases, drums, crates, bags, boxes, and many other types of articles. Article handling systems that stack layers of articles on a pallet to load the pallet generally are known as palletizers (i.e., a “palletizer” is a pallet-loading machine). What is needed is a pallet system that facilitates the trend of reduced distribution cost and broadens the class of users who can take advantage of the new economies of distribution.
Conventional manual palletizers require significant worker interaction. The function of the manual machine is to eliminate lifting; the worker controls the movement of the article. In contrast, a fully automated palletizer may only require the user manually to place empty pallets, or to fill hoppers or carton magazines and the like. Many automatic palletizers load entire layers of articles at once.
There are several reasons why a user might choose to palletize a packaging line automatically. First, automatic palletizers do a better job of stacking a load and, therefore, reduce damages to articles during transit. Product damage during shipment or within automatic storage and retrieval systems (AS/RS systems) caused by irregular loads is now part of the payback analysis to justify a palletizer. Second, automatic palletizers avoid many employment-related issues. For example, it is challenging to retain employees in low-wage, low-prestige positions such as those encompassing manual palletizing. The United States Occupational Safety and Health Administration (OSHA) standards regarding weight and repetitive motion limitations can be difficult to follow. And job-related back injuries are costly and can increase a company's insurance premiums. Third, production speeds in some packaging lines are past the point where articles can be hand stacked. Finally, a new generation of low-price, small foot print palletizers are on the market. These systems make it an easier investment decision even for slow-speed lines. All of these reasons justify automating a palletizing operation.
Automatic palletizers can be grouped into one of two main technologies: traditional or robotic. In turn, traditional automatic palletizers break down into two main categories based on how articles enter the machines. First, low-level traditional palletizers intake a continual flow of articles at ground level. Although fast, low-level traditional palletizers are not best for fragile items. Second, high-level traditional palletizers are similar to their low-level counterparts. They do not handle fragile items well, but they intake and load a continual flow of articles quickly. The difference is that high-level traditional palletizers intake from an elevated hopper.
A traditional palletizer arranges the articles that are delivered by a conveyor into a given pattern onto a stripper plate and places the patterned layer onto the pallet. Traditional palletizers can have low speeds or high speeds. As an example, a low-speed palletizer might stack 1-10 cases per minute while a high-speed palletizer might stack over 150 cases per minute. Both low-speed and high-speed traditional palletizers can have a floor-level infeed, fixed at three feet, or a high-level infeed fixed at ten feet. In general, if the production requirement is high speed, a traditional palletizer is the most likely solution.
In contrast to their traditional counterparts, robotic palletizers pick up, manipulate, and load single articles at a time. Robotic palletizers often cost more than traditional palletizers. On the other hand, robotic palletizers are advisable for fragile articles. A robotic palletizer uses an end effector (or gripper) to pick-up the article that is delivered by the conveyor and place the article onto the pallet. Robotic palletizing solutions come in four basic designs: Cartesian (the Cartesian coordinate system is used to determine each point uniquely in a plane through two numbers, usually called the x-coordinate or abscissa and the y-coordinate or ordinate of the point), SCARA (Selective Compliant Assembly Robot Arm), articulating arm, and gantry (a crane having a hoist fitted in a trolley for horizontal movement). The most prevalent palletizing robot is the articulating arm. It is the most flexible and allows for the fastest speeds. In general, robotic palletizers are the most flexible palletizing systems.
Palletizers typically are designed to stack as many as 30-40 boxes or other articles on a relatively large pallet Therefore, these systems must be relatively large to accommodate fully stacked pallets—so large, in fact, that they are typically fixed in one location and are not easily moved. Stacks of pallets instead are conveyed to and from the article handling system by dedicated conveyors, which further increase the space requirements of the system. Another problem associated with standard palletizers is that they are poorly suited for rapidly handling a relatively small numbers of articles. Consequently, palletizers used in these applications must routinely handle partially loaded pallets with an over-sized system that operates at less than one-third to one-half of its capacity at a considerable waste of space and resources. In summary, conventional palletizers are typically mounted directed to the floor of the plant, are large in size, and may cost on the order of $800,000.
The best palletizing system and the best method of palletizing is the one that takes advantage of the plant constraints at the least delivered cost while requiring the least amount of valuable floor space. For any set of plant conditions, the answer can be different. Among the factors that influence the choice of a palletizing system and method are: (1) production throughput, (2) available space, (3) traffic patterns, (4) distance from the packaging area to the palletizing area, (5) type of secondary packaging, (6) the frequency of changes in the stock keeping unit (or SKU which is a unique identifier for each distinct product and service that can be ordered from a supplier) in each production line, (7) stability requirements of the finished load, (8) whether articles are palletized on a pallet or a slip sheet or as a unitized load, (9) whether stretch wrappers are incorporated in the design, (10) whether any wash-down requirements exist, (11) the number of different products and patterns, and (12) the available AS/RS interface.
Conventional palletizing systems are available from a number of sources. Columbia Machine, Inc. of Vancouver, Wash. and Dyco, Inc. of Bloomsburg, Pa. offer palletizers and palletizer accessories. Conveying Industries, Inc. of Denver, Colo. custom builds palletizers to fit particular application needs. PASCO of St. Louis, Mo. is another custom builder that offers a wide array of palletizers. Some palletizers are adaptable, but these machines differ widely depending on exact application specifications. TopTier, Inc. of Portland, Oreg. manufactures simple palletizers with modular designs for flexibility. They also have palletizers that include stretch wrap capabilities.
Quality palletizers last a long time and refurbish well. Used palletizers are a viable option for saving some capital. The Frain Group of Franklin Park, Ill. and Sigma Packaging of Evansville, Ind. are used-palletizer specialists, offering many palletizers including combination systems. Their prices range from $2,500 to $125,000. Rental palletizer equipment is yet another palletizing option.
To overcome the shortcomings of conventional palletizers, a mobile split palletizer is provided. An object of the present invention is to provide an improved palletizer having the versatility needed to operate in connection with a wide variety of packaging lines and to accommodate various types and sizes of articles. A related object is to provide a palletizer capable of handling relatively small numbers of articles. Another object is to provide a palletizer that can be disassembled, moved, and re-assembled both quickly and easily with minimal manpower. Yet another object is to provide an economical, compact palletizer that saves money and space when installed in a plant or factory. It is still another object of the present invention to provide a palletizer that is tough, easy to use, and reliable.